I find the best way to win this fight is to not overthink it.
None of the enemies are immortal flagged or anything of the like, so status works. Evasion technically works, but Hell Knights can perform so many attacks they ARE going to hit you unless you reset like a whore until perfection occurs. They dish out lots of speed and damage, but unless your level is really high their HP should still be reasonable enough to kill them in one or two high-power hits.
I found the best way to win this fight was to be very aggressive. You can't outspeed them in most cases, so focus on raw power. If you use a Ninja, use a Martial Arts variant with max PA, etc. I just hit one or two of them with a Mimic Daravon on the first turn (and missed almost every Talk Skill after that until I was down to one enemy and stealing all his items) and aggro'd out the rest with Martial Arts Ninja, Two Hands Lancer, high power Draw Outs, etc. I actually got the fight on my first try with that setup (only having attempted it once before that), and the luck was really middling between teams if I remember right, so you don't really need to get "lucky" with an aggressive strategy, unlike some others. Your enemy can still be hit hard enough to make die because they don't have boss innates. Your enemy can still be status'd. Your enemy can still be made into Crystals and Chests if the counter runs out. Etc.
Yes, they have a lot of speed. Yes, they can hit you really fucking hard. Yes, they will probably rape you your first time through the fight, and possibly times after that. That doesn't mean uber setup is needed though. Just focus on the things your setup can do equal to or better than them (raw damage, status, higher HP, evasion if things REALLY aren't panning out well for you) and keep a clear head. Outside the ones near Ramza, their first turn can only be Untruth Skills, and a good PBF can really minimize what damage those do even if they get lucky, meaning their first turn on that half of the map can easily be chalked up to "coming into your kill range".
Maybe it's just me, but I find this fight to be rather overrated unless you're doing a Level 1 run (which is its own can of worms) or are some really high level where Hell Knight growths really begin to rape you. It's a really dangerous enemy team, sure, but none of my experiences with it really make me want to chalk it up to "specialize or die". Good planning and playing to what strengths your team can have over them on a basic level has always been enough for me with this fight. Let them go first, be ready for it, then hit them with debilitating statuses like Charm/Sleep/etc and hit them like a truck. They WILL die.